Ecology, Environment and Conservation Paper

EVALUATION OF POST EMERGENT HERBICIDES IN BT COTTON (GOSSYPIUM HIRSUTUM L.) UNDER UKP COMMAND AREA OF KARNATAKA, INDIA

Rajanand Hiremath, G. S. Yadahalli, V.G. Yadahalli, B.M. Chittapur, B.G. Koppalkar and S.N. Vinoda Kumar

Abstract

A field experiment was conducted during the growing season of 2012-13 at Agricultural College Farm, Bheemarayanagudi, Shahapur (Karnataka) under UKP command area to develop effective weed management strategy in Bt cotton. The experiment comprised of 14 treatments having two PRE (diuron, pendimethalin) and five POST (propaquizafop, quizalofop p tefuryl, fenoxaprop p ethyl, quizalofop ethyl and pyrithiobac sodium applied twice at 20 and 40 DAS individually or in sequence with pendimethalin PRE) herbicides and weedy and weed-free check. Pyrithiobac sodium 10 EC used alone twice or in sequence with pendimethalin PRE recorded lower weed dry weight and higher weed control efficiency throughout. Of all the herbicidal treatments, pendimethalin 38.7 CS @ 1.5 kg a.i. ha-1PRE fb pyrithiobac sodium 10 EC @ 1.25 kg a.i. ha-1 POST + IC at 60 DAS recorded the lowest weed dry matter, weed index, nutrient depletion, highest seed cotton yield (2569 kg ha-1) and gross returns (107885 Rs. ha-1). Pendimethalin 38.7 CS PRE followed with quizalofop ethyl 5 EC @ 0.05 kg a.i. ha-1or propaquizalofop 10 EC @ 0.1 kg a.i. ha- 1 at 30-35 DAS were the next efficient treatments.